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Articles 4651 - 4680 of 21795

Full-Text Articles in Engineering

A Threshold To Utilize Guayule Resin As A New Binder In Flexible Pavement Industry, Ahmed Hemida, Magdy Abdelrahman Dec 2018

A Threshold To Utilize Guayule Resin As A New Binder In Flexible Pavement Industry, Ahmed Hemida, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study denotes a threshold to utilize Guayule Resin as a new bio-based binder or asphalt cement (AC) proportion, both with/out crumb rubber modifier (CRM), regarding solutions for environment, cost, and sustainability aspects. Via this research, 15 designated binders will be presented, all of them were tested as unaged and RTFO, whereas eight binders proceeded with PAV. Superpave was utilized to study their physical properties. Viscosity was examined upon some guayule-based binders with/out CRM, getting 114cP (at 135℃) for BGR, increased to about 3 times with 10%CRM (by weight of liquid binder) and about 7-8 times with 20%CRM. Comparisons among …

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Marine Boundary Layer Aerosol In The Eastern North Atlantic: Seasonal Variations And Key Controlling Processes, Guangjie Zheng, Yang Wang, For Full List Of Authors, See Publisher's Website. Dec 2018

Marine Boundary Layer Aerosol In The Eastern North Atlantic: Seasonal Variations And Key Controlling Processes, Guangjie Zheng, Yang Wang, For Full List Of Authors, See Publisher's Website.

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The response of marine low cloud systems to changes in aerosol concentration represents one of the largest uncertainties in climate simulations. Major contributions to this uncertainty are derived from poor understanding of aerosol under natural conditions and the perturbation by anthropogenic emissions. The eastern North Atlantic (ENA) is a region of persistent but diverse marine boundary layer (MBL) clouds, whose albedo and precipitation are highly susceptible to perturbations in aerosol properties. In this study, we examine MBL aerosol properties, trace gas mixing ratios, and meteorological parameters measured at the Atmospheric Radiation Measurement Climate Research Facility's ENA site on Graciosa Island, …

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Preformed-Particle-Gel Placement And Plugging Performance In Fractures With Tips, Ze Wang, Baojun Bai Dec 2018

Preformed-Particle-Gel Placement And Plugging Performance In Fractures With Tips, Ze Wang, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Preformed-particle gels (PPGs) have been applied for reducing excessive water production caused by fractures in reservoirs. A portion of the fractures existing in reservoirs is composed of a void part and a fracture tip. The PPG placement behavior and plugging performance could be mainly affected by the fracture tips. A fracture with a tip, called a "partially open fracture" in this paper, was designed to investigate the placement and water-plugging performance of PPG. Cylindrical sandstone cores were used to manufacture partially open fractures. Pressure data of PPG injection, post-gel water breakthrough, and stable injection were analyzed to investigate the PPG …

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On-Demand Band-Rejected Wideband Antenna Based On Peelable Resonator Membrane, Rong Wang, Min Li, Salahuddin Raju, Robert C. Roberts, Mansun Chan, Lijun Jiang Dec 2018

On-Demand Band-Rejected Wideband Antenna Based On Peelable Resonator Membrane, Rong Wang, Min Li, Salahuddin Raju, Robert C. Roberts, Mansun Chan, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this letter, we present a wideband planar antenna with on-demand band-rejected characteristics based on the peelable double electric-LC (DELC) resonator membranes. By applying microfabrication techniques, the subwavelength DELC structure is completely encapsulated in a transparent and flexible thin film with a total thickness of 10 mum. Resonators with four different widths (4.0, 3.6, 3.2, 2.8 mm) are packaged as a solution kit, providing the rejection bands of 4.24-5.11, 4.61-5.38, 4.85-5.48, and 5.20-5.70 GHz, respectively. Owing to the passive and detachable features of this functional sticker, no biasing network is needed for the rejection band's on/off transition and the membrane …

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Data-Enabled Computational Multiscale Method In Materials Science And Engineering, Shaoping Xiao, Amaury Lendasse, Renjie Hu Dec 2018

Data-Enabled Computational Multiscale Method In Materials Science And Engineering, Shaoping Xiao, Amaury Lendasse, Renjie Hu

Engineering Management and Systems Engineering Faculty Research & Creative Works

In the Community of Computational Materials Science, One of the Challenges in Hierarchical Multiscale Modeling is Information-Passing from One Scale to Another, especially from the Molecular Model to the Continuum Model. a Machine-Learning-Enhanced Approach, Proposed in This Paper, Provides an Alternative Solution. in the Developed Hierarchical Multiscale Method, Molecular Dynamics Simulations in the Molecular Model Are Conducted First to Generate Datasets, Which Represents Physical Phenomena at the Nanoscale. the Datasets Are Then Used to Train Neural Networks for Failure Classification and Stress Regressions. Finally, the Well-Trained Learning Machines Are Implemented in the Continuum Model to Study the Mechanical Behaviors of …

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Blood-Based Biomarkers For Predicting The Risk For Five-Year Incident Coronary Heart Disease In The Framingham Heart Study Via Machine Learning, Meeshanthini V. Dogan, Steven R.H. Beach, Ronald L. Simons, Amaury Lendasse, Brandan Penaluna, Robert A. Philibert Dec 2018

Blood-Based Biomarkers For Predicting The Risk For Five-Year Incident Coronary Heart Disease In The Framingham Heart Study Via Machine Learning, Meeshanthini V. Dogan, Steven R.H. Beach, Ronald L. Simons, Amaury Lendasse, Brandan Penaluna, Robert A. Philibert

Engineering Management and Systems Engineering Faculty Research & Creative Works

An Improved Approach for Predicting the Risk for Incident Coronary Heart Disease (CHD) Could Lead to Substantial Improvements in Cardiovascular Health. Previously, We Have Shown that Genetic and Epigenetic Loci Could Predict CHD Status More Sensitively Than Conventional Risk Factors. Herein, We Examine Whether Similar Machine Learning Approaches Could Be Used to Develop a Similar Panel for Predicting Incident CHD. Training and Test Sets Consisted of 1180 and 524 Individuals, respectively. Data Mining Techniques Were Employed to Mine for Predictive Biosignatures in the Training Set. an Ensemble of Random Forest Models Consisting of Four Genetic and Four Epigenetic Loci Was …

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Spin-Controlled Wavefront Shaping With Plasmonic Chiral Geometric Metasurfaces, Yang Chen, Xiaodong Yang, Jie Gao Dec 2018

Spin-Controlled Wavefront Shaping With Plasmonic Chiral Geometric Metasurfaces, Yang Chen, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Metasurfaces, as a two-dimensional (2D) version of metamaterials, have drawn considerable attention for their revolutionary capability in manipulating the amplitude, phase, and polarization of light. As one of the most important types of metasurfaces, geometric metasurfaces provide a versatile platform for controlling optical phase distributions due to the geometric nature of the generated phase profile. However, it remains a great challenge to design geometric metasurfaces for realizing spin-switchable functionalities because the generated phase profile with the converted spin is reversed once the handedness of the incident beam is switched. Here, we propose and experimentally demonstrate chiral geometric metasurfaces based on …

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Accelerated Freezing Due To Droplet Pinning On A Nanopillared Surface, Rachel Bohm, Mohammad Rejaul Haque, Chuang Qu, Edward C. Kinzel, Amy Rachel Betz Dec 2018

Accelerated Freezing Due To Droplet Pinning On A Nanopillared Surface, Rachel Bohm, Mohammad Rejaul Haque, Chuang Qu, Edward C. Kinzel, Amy Rachel Betz

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The freezing process is significantly influenced by environmental factors and surface morphologies. At atmospheric pressure, a surface below the dew and freezing point temperature for a given relative humidity nucleates water droplets heterogeneously on the surface and then freezes. This paper examines the effect of nanostructured surfaces on the nucleation, growth, and subsequent freezing processes. Microsphere Photolithography (MPL) is used to pattern arrays of silica nanopillars. This technique uses a self-assembled lattice of microspheres to focus UV radiation to an array of photonic jets in photoresist. Silica is deposited using e-beam evaporation and lift-off. The samples were placed on a …

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Synergic Titanium Nitride Coating And Titanium Doping By Atomic Layer Deposition For Stable- And High-Performance Lifepo₄, Yan Gao, Jonghyun Park, Xinhua Liang Dec 2018

Synergic Titanium Nitride Coating And Titanium Doping By Atomic Layer Deposition For Stable- And High-Performance Lifepo₄, Yan Gao, Jonghyun Park, Xinhua Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Atomic layer deposition (ALD) method has emerged as a promising technique to address the dissolution and poor conductivity of electrode materials of lithium ion batteries. In this work, surface modification of LiFePO4 (LFP) was carried out by titanium nitride (TiN) ALD, during which a Ti doping into LFP occurred simultaneously. X-ray photoelectron spectroscopy (XPS) and electrochemical tests were performed to prove the Ti doping, and the composition of TiN layer on the surface of LFP particles was interpreted as a combination of TiN and titanium oxynitride (TiOxNy). Owing to the synergy of TiN coating and …

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Assessment Of Small-Scale Anisotropy In Stably Stratified Turbulent Flows Using Direct Numerical Simulations, Amrapalli Garanaik, Subhas Karan Venayagamoorthy Dec 2018

Assessment Of Small-Scale Anisotropy In Stably Stratified Turbulent Flows Using Direct Numerical Simulations, Amrapalli Garanaik, Subhas Karan Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, the validity of the widely used Kolmogorov hypothesis of local isotropy of dissipative scales in stably stratified turbulent flows is investigated using high-resolution direct numerical simulations. Departure from isotropy is investigated for the first time in terms of the turbulent Froude number defined as Fr = ϵ/(NEk), where N is the buoyancy frequency, Ek is the turbulent kinetic energy, and ϵ is the rate of dissipation of turbulent kinetic energy. It is shown that for both ϵ and the rate of scalar (density) dissipation, ϵρ, the small-scale statistics are nearly isotropic in the weakly stratified turbulent regime …

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A Wideband 2-D Fast Multipole Algorithm With A Novel Diagonalization Form, Ling Ling Meng, Mert Hidayetoǧlu, Tian Xia, Wei E.I. Sha, Li (Lijun) Jun Jiang, Weng Cho Chew Dec 2018

A Wideband 2-D Fast Multipole Algorithm With A Novel Diagonalization Form, Ling Ling Meng, Mert Hidayetoǧlu, Tian Xia, Wei E.I. Sha, Li (Lijun) Jun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

It is well known that Green's function can be expressed by multipole expansion, plane-wave expansion, and exponential expansion (spectral representation). These three expansions constitute of the foundations of the fast multipole algorithm (FMA). The plane-wave expansion has the low-frequency breakdown issue due to its failure in capturing the evanescent spectra, while the multipole expansion is inefficient at high frequencies. The spectral representation usually involves in direction-dependent issue. In this communication, the 2-D FMA is interpreted as Parseval's theorem in Fourier transform. To achieve a stable and accurate transition between the multipole expansion and the plane-wave expansion, a novel diagonalization in …

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Dual-Band Filtering Antenna With Novel Transmission Zero Characteristics, Kirti Dhwaj, Li (Lijun) Jun Jiang, Tatsuo Itoh Dec 2018

Dual-Band Filtering Antenna With Novel Transmission Zero Characteristics, Kirti Dhwaj, Li (Lijun) Jun Jiang, Tatsuo Itoh

Electrical and Computer Engineering Faculty Research & Creative Works

A single-layer two-pole dual-band filtering antenna (DBFA) with orthogonal polarizations in the two bands is presented in this letter. The DBFA is based on a common dual-mode T-shaped resonator (TR). The two modes of the common resonator each couple to one of the two orthogonally placed patches, resulting in required radiation. The TR is responsible for generation of three transmission zeroes (TZs) in frequency response corresponding to each polarization at the broadside: two of them being intrinsic TZs due to the TR and the third caused by far field interference of TR's radiation with that of the patch. The low …

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Applications Of Node-Based Resilience Graph Theoretic Framework To Clustering Autism Spectrum Disorders Phenotypes, John Matta, Junya Zhao, Gunes Ercal, Tayo Obafemi-Ajayi Dec 2018

Applications Of Node-Based Resilience Graph Theoretic Framework To Clustering Autism Spectrum Disorders Phenotypes, John Matta, Junya Zhao, Gunes Ercal, Tayo Obafemi-Ajayi

Electrical and Computer Engineering Faculty Research & Creative Works

With the growing ubiquity of data in network form, clustering in the context of a network, represented as a graph, has become increasingly important. Clustering is a very useful data exploratory machine learning tool that allows us to make better sense of heterogeneous data by grouping data with similar attributes based on some criteria. This paper investigates the application of a novel graph theoretic clustering method, Node-Based Resilience clustering (NBR-Clust), to address the heterogeneity of Autism Spectrum Disorder (ASD) and identify meaningful subgroups. The hypothesis is that analysis of these subgroups would reveal relevant biomarkers that would provide a better …

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Capillary-Tube Package Devices For The Quantitative Performance Evaluation Of Nuclear Magnetic Resonance Spectrometers And Pulse Sequences, Lingyu Chi, Ming Huang, Annalise R. Pfaff, Jie Huang, Rex E. Gerald Ii, Klaus Woelk Dec 2018

Capillary-Tube Package Devices For The Quantitative Performance Evaluation Of Nuclear Magnetic Resonance Spectrometers And Pulse Sequences, Lingyu Chi, Ming Huang, Annalise R. Pfaff, Jie Huang, Rex E. Gerald Ii, Klaus Woelk

Electrical and Computer Engineering Faculty Research & Creative Works

With the increased sensitivity of modern nuclear magnetic resonance (NMR) spectrometers, the minimum amount needed for chemical-shift referencing of NMR spectra has decreased to a point where a few microliters can be sufficient to observe a reference signal. The reduction in the amount of required reference material is the basis for the NMR Capillary-tube Package (CapPack) platform that utilizes capillary tubes with inner diameters smaller than 150 µm as NMR-tube inserts for external reference standards. It is shown how commercially available electrophoresis capillary tubes with outer diameters of 360 µm are filled with reference liquids or solutions and then permanently …

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Macro-/Micro-Controlled 3d Lithium-Ion Batteries Via Additive Manufacturing And Electric Field Processing, Jie Li, Xinhua Liang, Frank W. Liou, Jonghyun Park Dec 2018

Macro-/Micro-Controlled 3d Lithium-Ion Batteries Via Additive Manufacturing And Electric Field Processing, Jie Li, Xinhua Liang, Frank W. Liou, Jonghyun Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

This paper presents a new concept for making battery electrodes that can simultaneously control macro-/micro-structures and help address current energy storage technology gaps and future energy storage requirements. Modern batteries are fabricated in the form of laminated structures that are composed of randomly mixed constituent materials. This randomness in conventional methods can provide a possibility of developing new breakthrough processing techniques to build well-organized structures that can improve battery performance. In the proposed processing, an electric field (EF) controls the microstructures of manganese-based electrodes, while additive manufacturing controls macro-3D structures and the integration of both scales. The synergistic control of …

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Superelastic And Ph-Responsive Degradable Dendrimer Cryogels Prepared By Cryo-Aza-Michael Addition Reaction, Juan Wang, Hu Yang Dec 2018

Superelastic And Ph-Responsive Degradable Dendrimer Cryogels Prepared By Cryo-Aza-Michael Addition Reaction, Juan Wang, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Dendrimers exhibit super atomistic features by virtue of their well-defined discrete quantized nanoscale structures. Here, we show that hyperbranched amine-terminated polyamidoamine (PAMAM) dendrimer G4.0 reacts with linear polyethylene glycol (PEG) diacrylate (575 g/mol) via the aza-Michael addition reaction at a subzero temperature (-20 °C), namely cryo-aza-Michael addition, to form a macroporous superelastic network, i.e., dendrimer cryogel. Dendrimer cryogels exhibit biologically relevant Young's modulus, high compression elasticity and super resilience at ambient temperature. Furthermore, the dendrimer cryogels exhibit excellent rebound performance and do not show significant stress relaxation under cyclic deformation over a wide temperature range (-80 to 100 °C). The …

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Experimental Study On The Influence Of Slickwater On Shale Permeability, Zhonghua Liu, Baojun Bai, Zheyu Zhang, Jing Tang, Shunpeng Zeng, Xiaogang Li Dec 2018

Experimental Study On The Influence Of Slickwater On Shale Permeability, Zhonghua Liu, Baojun Bai, Zheyu Zhang, Jing Tang, Shunpeng Zeng, Xiaogang Li

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

There are two diametrically opposite views of the influence of slickwater on shale permeability among scholars at home and abroad. We used the shale outcrops rock samples from the Lower Silurian Longmaxi Formation in Sichuan Basin. The permeability of these dry samples before and after immersion in different solution systems were tested by pulse attenuation method. The experimental results show that the impregnation of different slickwater components and standard salt solution can promote the increase of the permeability of shale samples. The stress sensitivity of shale samples after liquid immersion is medium weak to weak. The sample stress sensitivity is …

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A Note Of Thanks To John Halloran, William Fahrenholtz Dec 2018

A Note Of Thanks To John Halloran, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Cell For Flow Battery, Jonghyun Park, Mohammed Abdulkhabeer Al-Yasiri Nov 2018

Cell For Flow Battery, Jonghyun Park, Mohammed Abdulkhabeer Al-Yasiri

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A reaction cell for a flow battery having flow channels positioned within a recess of a non-porous and non-brittle housing that is also a dielectric. Positioning the flow channels within the recess eliminates the need for end plates, gaskets, and insulators of conventional designs. A current collector and an electrode within the recess have areas approximately equal to the area of the recess such that they fit within the recess and maximize the contact area between them.

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Highly Porous Ceramic Material And Method Of Using And Forming The Same, Alan W. Weimer, Xinhua Liang Nov 2018

Highly Porous Ceramic Material And Method Of Using And Forming The Same, Alan W. Weimer, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

The present invention generally relates to porous ceramic material and to methods of making and using the material. More particularly, the invention relates to methods of forming ceramic materials by depositing material, using atomic layer deposition, onto a sacrificial substrate and to ceramic materials having controlled wall thickness, relatively large pores, and high surface area by weight.

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Planar Resonator Embedded Substrate Integrated Waveguide (Siw) Cavity Filter, Kirti Dhwaj, Richard Hadi, Tao Yang, Li (Lijun) Jun Jiang, Joshu Kovitz, Tatsuo Itoh Nov 2018

Planar Resonator Embedded Substrate Integrated Waveguide (Siw) Cavity Filter, Kirti Dhwaj, Richard Hadi, Tao Yang, Li (Lijun) Jun Jiang, Joshu Kovitz, Tatsuo Itoh

Electrical and Computer Engineering Faculty Research & Creative Works

Two capacitor loaded planar resonators are introduced in a two-cavity substrate integrated waveguide (SIW) structure to obtain a fourth order filter. The planar resonators each produce a transmission zero by signal interference. Design methodology for a 5 % bandwidth bandpass filter operating at 2.35 GHz is presented in the paper. Two transmission zeroes are placed on either side of the filter passband to obtain a quasi-elliptic response with a mid-band inserion loss of 1.65 dB. Good agreement is obtained between measured and simulated responses of the single-layer printed circuit board (PCB) filter.

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Blazed Metasurface Grating With Handedness Preservation For Circularly Polarized Incident Wave, Xiaoqiang Li, Cheng Tao, Lijun Jiang, Tatsuo Itoh Nov 2018

Blazed Metasurface Grating With Handedness Preservation For Circularly Polarized Incident Wave, Xiaoqiang Li, Cheng Tao, Lijun Jiang, Tatsuo Itoh

Electrical and Computer Engineering Faculty Research & Creative Works

A new blazed metasurface grating for circularly polarized (CP) incident wave operating at 10 GHz is proposed. Such a structure can provide strong auto-collimation for the CP incident wave. Unlike the conventional scatterer, which typically reverses the handedness of the incident CP wave upon reflection, the proposed grating can preserve the handedness. The auto-collimation blazing effect and handedness preservation are achieved by a specially designed reactive impedance surface, which allows independent response controls to transverse electric (TE) and transverse magnetic (TM) polarizations. The proposed idea is demonstrated by simulations and verified by experiments. Comparisons with conventional sawtooth grating are made …

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Silica Nanoparticle-Endothelial Interaction: Uptake And Effect On Platelet Adhesion Under Flow Conditions, Jiban Saikia, Raziye Mohammadpour, Mostafa Yazdimamaghani, Hannah Northrup, Vladimir Hlady, Hamidreza Ghandehari Nov 2018

Silica Nanoparticle-Endothelial Interaction: Uptake And Effect On Platelet Adhesion Under Flow Conditions, Jiban Saikia, Raziye Mohammadpour, Mostafa Yazdimamaghani, Hannah Northrup, Vladimir Hlady, Hamidreza Ghandehari

Chemical and Biochemical Engineering Faculty Research & Creative Works

Silica nanoparticles are extensively used in biomedical applications and consumer products. Little is known about the interaction of these NPs with the endothelium and effect on platelet adhesion under flow conditions in circulation. In this study, we investigated the effect of silica nanoparticles on the endothelium and its inflammation, and subsequent adhesion of flowing platelets in vitro. Platelet counts adhered onto the surface of endothelial cells in the presence of nanoparticles increased at both low and high concentrations of nanoparticles. Preincubation of endothelial cells with nanoparticles also increased platelet adhesion. Interestingly, platelet adhesion onto TNF-α-treated endothelial cells decreased in the …

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Apparatus, Methods And Systems For Fabricating Thin Nanoporous Membranes, Sankar Nair, Jeffrey H. Drese, Kiwon Eum, Ryan P. Lively, Ali A. Rownaghi, Yash Tamhankar, Shaowei Yang Nov 2018

Apparatus, Methods And Systems For Fabricating Thin Nanoporous Membranes, Sankar Nair, Jeffrey H. Drese, Kiwon Eum, Ryan P. Lively, Ali A. Rownaghi, Yash Tamhankar, Shaowei Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Embodiments of the present disclosure provide apparatuses, methods and systems for scalable fabrication of thin, nanoporous membranes useful in industrial applications. One embodiment of the present disclosure provides a molecular separation device configured to efficiently separate molecular species. In this particular embodiment, porous hollow fibers form a supporting scaffold for synthesis of a molecular organic framework (MOF) membrane. The MOF membrane may be synthesized on the inner or outer porous hollow fiber surface as well as within the porous fiber wall. Embodiments of the present disclosure provide a variety of methods for producing the aforementioned molecular separation devices as well …

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A New Efficient Domain Decomposition Method For Highly Irregular Via Patterns, Ping Li, Lijun Jiang, Xiaoyan Xiong, Hakan Bagci Nov 2018

A New Efficient Domain Decomposition Method For Highly Irregular Via Patterns, Ping Li, Lijun Jiang, Xiaoyan Xiong, Hakan Bagci

Electrical and Computer Engineering Faculty Research & Creative Works

In the high-speed signal path on PCB and packagings, vias usually causes most discontinuities and thereby crosstalks. In simulation and characterizations, they also generate more errors than the trace parts due to rich modes around them. To achieve both efficiency and accuracy, in this paper, a new domain decomposition based finite element time domain (FETD) method is proposed for the analysis of power/ground plate pairs with various types of antipads. Using the magnetic field feature, the 3D computational domain is firstly represented by a quasi-2D field. Then by taking advantage of the fast decaying property of high order modes, the …

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Biaxial Bending Of Cold-Formed Steel Storage Rack Uprights – Part I: Parametric Studies And Response, Nima Talebian, Benoit P. Gilbert, Cao Hung Pham, Romain Chariere, Hassan Karampour Nov 2018

Biaxial Bending Of Cold-Formed Steel Storage Rack Uprights – Part I: Parametric Studies And Response, Nima Talebian, Benoit P. Gilbert, Cao Hung Pham, Romain Chariere, Hassan Karampour

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper first introduces an advanced finite element model to determine the biaxial bending capacity of cold-formed steel storage rack upright sections. The model is found to accurately predict published experimental results with an average predicted to experimental capacity ratio of 1.02. Second, the validated model is used to run parametric studies and analyse the biaxial response of slender, semi-compact and compact unperforated storage rack upright cross-sections. Analyses are run for local and distortional buckling failure modes only. Ten and four different cross-sectional shapes are analysed for local and distortional buckling, respectively, and nine biaxial bending configurations are considered per …

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Sidelap And Structural Fastener Tests For Steel Deck Diaphragms, Y. Shi, S. Torabian, Benjamin W. Schafer, W. S. Easterling, M. R. Eatherton Nov 2018

Sidelap And Structural Fastener Tests For Steel Deck Diaphragms, Y. Shi, S. Torabian, Benjamin W. Schafer, W. S. Easterling, M. R. Eatherton

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Steel deck diaphragm systems, which are commonly used for roof construction in steel-framed buildings, consist of many parts such as corrugated steel deck sheets, sidelap fasteners between adjacent sheets, structural fasteners from the sheets to the supporting beams or joists, chord elements, and collectors. Load-deformation behavior of a steel deck diaphragm system is typically dominated by sidelap and structural fastener limit states. To understand and accurately model the behavior of steel deck diaphragm systems, it is therefore necessary to characterize the behavior of the individual fasteners. The effect of local geometry and detailing at these fasteners such as how the …

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The 2017 Aisi Cold-Formed Steel Design Manual, Joshua Buckholt, Helen Chen Nov 2018

The 2017 Aisi Cold-Formed Steel Design Manual, Joshua Buckholt, Helen Chen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The 2017 edition of AISI D100, the Cold-Formed Steel Design Manual (Manual) has been published. Updates to the Manual include: alignment with AISI S100-16, the North-American Specification for the Design of Cold-Formed Steel Structural Members (NA Specification); several new and varied design examples; additional discussions related to the design of cold-formed steel structures and components; and expanded bibliographies of relevant resources. The database of examples illustrating the Direct Strength Method (DSM) and new provisions in the NA Specification has been expanded. Also published with the Manual are the North-American Specification and its Commentary.

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Distortional Buckling Of Cold-Formed Steel Flanges Under Stress Gradient, Robert S. Glauz Nov 2018

Distortional Buckling Of Cold-Formed Steel Flanges Under Stress Gradient, Robert S. Glauz

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The strength of cold-formed steel beams with stiffened flanges may be controlled by distortional buckling. Buckling stress prediction methods have been developed for flanges under uniform compression. However, channel sections are commonly used where bending occurs about the minor axis with flanges under stress gradient, such that the edges are in compression and the flanges may experience distortional buckling. Current design specifications do not explicitly address this failure mode, which could lead to unsafe designs. This paper presents and verifies an analytical approach for distortional buckling stress prediction for flanges under stress gradient. The approach is consistent with the design …

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Tensile Strength And Serviceability Of Cold-Formed Steel Clip Angles, Wenying Zhang, Zhishan Yan, Mahsa Mahdavian, Mohamad Yousof, Cheng Yu Nov 2018

Tensile Strength And Serviceability Of Cold-Formed Steel Clip Angles, Wenying Zhang, Zhishan Yan, Mahsa Mahdavian, Mohamad Yousof, Cheng Yu

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper reports the recent research findings of cold-formed steel clip angles in tension. The relevant experimental program and the proposed design methods are presented. The test program involved two phases of testing: Phase I of program focused on the pull-over strength of screw connections on the anchored leg of the clip angles, and Phase II of program concentrated on the tensile strength of the anchored leg of the clip angles within the service deflection limit. Design methods for predicting the pull-over strength as well as tensile strength within the serviceability deformation limit are proposed based on the test results …

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